A Dunbarton farmer will have the chance to explain his proposal for a 27,000-square-foot poultry barn on his property at a planning board hearing tomorrow. And for Dunbarton residents feeling foul about the 20,000 birds Tom Giovagnoli’s building would house, the public hearing will be a chance to voice their concerns.

Giovagnoli has asked the town’s permission to build the coop, which would be 46 feet wide and 588 feet long, near the center of his 85-acre farm on Twist Hill Road. He already has a contract to sell the chickens’ eggs to Monroe-based Pete and Gerry’s Organic Eggs, which has provided the design for the building.

The farmer first appeared before the planning board in April, and neighbors raised a number of concerns with his proposal – the smell, the size of the operation, and its effect on local water and air, as well as on their property values.

So Giovagnoli will appear before the planning board and his abutters again tomorrow, but he won’t go alone. He said representatives from Pete and Gerry’s, the University of New Hampshire and the New Hampshire Farm Bureau Federation will attend the meeting to help him argue his case and answer his neighbors’ questions.

“At the end of the day, they’re not going to see (the coop),” Giovagnoli said of his neighbors. “They’re not going to hear it. They think they’re going to smell it.”

At the hearing, Giovagnoli will explain the mechanized coop – called an organic layer barn – he wants to build. In a layer barn, Giovagnoli said the hens sit on a grated floor about a foot off the ground, which allows their waste to drop to a lower level. An automated scraper pushes the manure to the back of the barn, where it’s kept in an enclosed concrete pit that is emptied every few months.

“At the meeting, we’re going to try (to show) everybody how the manure is managed and why it’s not going to smell,” he said. “Hopefully, people will have an open mind.”

Selectmen Chairman Les Hammond sits on the planning board and said he’s expecting a crowd at the hearing.

“In this particular case, we’re talking about people’s largest asset – their home and their property. . . . From our point of view, it’s going through and reading what’s presented to us and balancing that, making sure everybody gets a fair shake,” Hammond said.

Hammond and another planning board member visited Pete and Gerry’s headquarters in Monroe shortly after Giovagnoli first came before the board in April. They took a tour of the company’s egg-processing facility and one of its four poultry barns that is nearly identical to the barn planned for Giovagnoli’s farm.

“I stood in that parking lot, and I could see very close by where those four chicken barns (are),” Hammond said. “I couldn’t smell anything. I couldn’t smell anything whatsoever.”

When Hammond got closer, he said he could identify only the smell of cow manure from a nearby dairy farm. Then he stepped inside the enclosure that holds the chicken manure – and took a whiff.

“I closed my eyes and stood right on the pile of manure and could not smell any manure at all,” he said.

Giovagnoli’s initial application left out some information the town needed, Hammond said, and he feels more prepared to consider Giovagnoli’s application now that he has seen – and smelled – a similar facility in Monroe. But the farmer will still need to make a complete presentation to the board and his abutters tomorrow night.

His presentation will need to “go over the gamut,” Hammond said. “It’s going to go over smell, pollution, the size of the operation. Is that going to be a problem with traffic? The location – is it going to compromise the water quality down there? Is it going to compromise the air quality? Just all kinds of things.”

A couple of hens wouldn’t raise such a concern for the town, Hammond said, but these chickens will be living in what he estimated would be the biggest building in Dunbarton.

“When you get to 20,000 (chickens) on one piece of land, that creates some other questions that need to be answered,” Hammond said.

Should the planning board approve the $60,000 barn, Giovagnoli said he will run a certified organic operation.

If he didn’t plan to keep the coop and his eggs organic, Giovagnoli said he would be able to build a coop as small as 3,000 square feet – nine times smaller than the barn he’s trying to get permission to build.

“The barn is not bigger because I have nine times more birds,” he said. “The barn is bigger because I need nine times more room for the same amount of birds (to be organic). So it sounds like a lot, but as an industry standard, a 20,000-hen operation is actually a fairly small operation.”

Giovagnoli, who was raised on a farm, said he watched his dad run his Manchester pig farm the organic way as he was growing up. No pesticides, no chemicals. Manure was the best fertilizer.

Now, he won’t have it any other way.

“That’s what I was taught to do,” Giovagnoli said. “That’s what I believe in.

Giovagnoli is ready to make his case tomorrow, but he has encouraged his neighbors to visit Pete and Gerry’s in Monroe to see the operation with their own eyes.

“All I tell the neighbors is, ‘Don’t listen to anything you hear. Don’t even listen to me. Go see for yourself,’ ” he said.

The hearing is at 7 p.m. tomorrow at the Dunbarton Community Center on Robert Rogers Road. Giovagnoli’s application and plans for the building are available for viewing at the town office.

(Megan Doyle can be reached at 369-3321 or mdoyle@cmonitor.com or on Twitter @megan_e_doyle.)